Answer:
Group 18th
Explanation:
The group 18th of periodic table which is composed of Noble gases mainly was missing from the Mendeleev's periodic table. The reason for this is that Noble gases are least reactive, therefore, it was difficult to predict such elements which do not react with other elements.
<span>b.mixtures are made up of more than one component</span>
Number of second in human lives in scientific notation is 3.9 × 10⁷ second
<u>Given that;</u>
Average human lives = 74 years
<u>Find:</u>
Number of second in human lives in scientific notation
<u>Computation:</u>
Number of second in human lives in scientific notation = 74 × 365 × 24 × 60
Number of second in human lives in scientific notation = 38,894,400
Number of second in human lives in scientific notation = 3.9 × 10⁷ second
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Covalent bond forms between the oxygen and hydrogen atoms.
(I attached a picture that could help)
-Hope that helps,
Good luck!
Answer:
atoms tend to react in order to gain 8 valence electrons
Explanation:
The octet rule describes the tendency of atoms of elements to react in order to have eight electrons in their valence shell. This is because having eight valence electrons confers stability to the atoms of these elements in the compounds they form.
The octet rule only does not apply to the transition elements or the inner transition elements as only the s and p electrons are involved. the electronic configuration in atoms having an octet is s²p⁶.
For example, sodium atom has one valence electron in its valence shell but a complete octet in the inner shell; it will react with chlorine atom which has seven valence electrons to form a stable compound, sodium chloride by donating its one valence electron in order to have an octet. Similarly, the chlorine atom will then have an octet by accepting the one electron from sodium atom.